To provide a method for constructing an economical foundation without using concrete, by an embedding method utilizing the weight of soil for a trestle foundation of a solar power generating facility installed on a ground.

In a trestle foundation of a solar power generation facility installed on a ground, wind 1 may cause the foundation to float. Therefore, in order to prevent the floating of the foundation without using concrete, a T-shaped structure made by jointing a bottom part flat plate 3 and a basic rear prop 2 together is embedded in the ground, and the foundation is prevented from floating by the weight of an upper resistant soil 5 surrounded by a repose angle above the flat plate.